EP3954462A1 - Comminuting device with cooling device and method of operating the same - Google Patents

Abstract

The invention relates to a comminution device which is designed to carry out a comminution process with a comminution rotor which is mounted on a machine frame and has a plurality of comminution tools on its circumference, the comminution rotor being arranged and embodied in a comminution space which accommodates the material to be comminuted and which is located in the comminution space Easy to crush, further comprising a coolant device which is designed to introduce a liquid coolant comprising at least 80% water into the crushing space, and comprising a control device for controlling the coolant device to adjust a rate at which the coolant is introduced into the crushing space. The comminution device according to the invention is characterized in that the control device is set up and configured to adapt an introduction rate of the liquid coolant into the comminution process to an operating parameter of the device dependent on the throughput of the material to be comminuted in such a way that more than 60% of the cooling capacity introduced into the material to be comminuted is latent heat of the liquid, water-based coolant is provided. The invention also relates to a method for operating a device.

Description

The invention relates to a comminution device, in which a comminution rotor is mounted on a machine frame and has a plurality of comminution tools on its circumference, the comminution rotor being arranged in a comminution chamber accommodating comminution material and being designed to comminute the material in the comminution chamber, further comprising a Coolant device which is designed to introduce a liquid, water-based coolant into the comminution space and comprising a control device for controlling the coolant device in order to adjust a rate at which the coolant is introduced into the comminution space.

Such crushing devices are well known in the field, in particular in the crushing of plastic materials, for example for the recovery of production residues or the recycling of plastic materials. In particular when processing plastics, but under certain circumstances also with other specific ones material to be comminuted, cooling of the material during the comminution process is necessary in order to prevent the process heat acting on the material to be comminuted during the comminution process from causing the material to become too hot, which under certain circumstances could affect the comminution process itself, which could result in cutting, breaking and/or tearing of the material requires, makes it more difficult or even causes an undesirable phase transition of the comminuted material, which can make subsequent further processing of the material to be ground more difficult or impossible.

Such a conventional comminution device, which is set up to cool the material to be comminuted during the comminution process, is disclosed in the published application, for example EP 1 364 713 A2 described. It is taught how to use a gas such as compressed air and/or a liquid such as cold water as a cooling medium in order to dissipate the process heat generated and thus prevent temperatures of the comminuted material being generated during the comminution process that are not conducive to this. The used, heated cooling medium is usually disposed of by removing the comminuted material or by using a separate device which, for example, leads the cooling medium through an external heat exchanger and makes it available for reuse in a closed circuit.

It has been found that the prior art comminution devices described, particularly in the case of thermally sensitive materials, often do not provide sufficient removal of the process heat to prevent an unwanted change of state or even ignition of the material during the comminution process. In addition, the disposal or recycling of the used, heated cooling medium in devices of the prior art is associated with an increased outlay on the device side and an increased outlay on maintenance of the comminuting device. Furthermore, particularly with the described conventional water cooling, the degree of moisture in the comminuted material can increase to such an extent that subsequent further processing of the material to be ground is made more difficult or leads to inferior products.

The object of the present invention is to at least partially eliminate the described disadvantages of conventional comminution devices according to the prior art. This object is achieved by a comminution device having the features of claim 1. The comminution device according to the invention has a comminution rotor, which is mounted on a machine frame and has a plurality of comminution tools on its circumference, the comminution rotor being arranged in a comminution space that accommodates the material to be comminuted and designed to comminute the material in the comminution space, with a Coolant device is provided, which is designed to introduce a liquid coolant having a water content of at least 80% into the crushing chamber. Furthermore, the comminution device according to the invention has a control device for controlling the coolant device for setting a rate of introduction of the coolant into the comminution space. The comminution device according to the invention is characterized in that the control device is set up and configured to adapt an introduction rate of the liquid, water-based coolant into the comminution process or the comminution space in which the comminution process takes place to an operating parameter dependent on the throughput of the material to be comminuted adapt the device, in particular a volume throughput, a mass throughput of the material to be comminuted and/or a drive power of a rotor drive, in particular a drive motor of the rotor, in such a way that more than 60% of the cooling capacity introduced into the material to be comminuted or the comminution space is cooled by the latent heat of the liquid, water-based coolant is provided. The specified throughput of the material to be comminuted, to which the introduction rate of the coolant is adjusted, can be the throughput of the material to be comminuted or the throughput of the material to be comminuted (ground material).

The comminution device according to the invention is based on the fundamental idea of designing a coolant device with appropriate control in such a way that a water-based liquid coolant is introduced into the comminution space in which the comminution process takes place and process heat is generated by the comminution process in such a way that the cooling capacity is essentially, in particular in a predominant proportion, is provided by the latent heat of the water-based coolant, so that an effective process heat removal can be provided with comparatively little coolant input, without increased temperatures of the comminuted material resulting, which can be detrimental to further processing of the comminuted material. Since the introduction rate of the coolant is adapted to the throughput of the shredded material that is processed in the shredding process, a possibly specified moisture content threshold of the shredded material (ground material) that makes further processing of the shredded material more difficult can be avoided or, under certain circumstances, the moisture content of the comminuted material can be set lower than the moisture content of the material supplied to the comminuting rotor. In this respect, the inventive Crushing device be designed and controlled so that at any time so much coolant is fed into the comminution process that an optimal cooling performance is provided and at the same time the coolant is essentially completely expelled by transition into the gaseous phase by evaporation or evaporation from the material during comminution will. The described control of the cooling device makes it possible to avoid an operating situation in which too much coolant is introduced into the comminution chamber, with the result that an increased proportion of cooling is provided by the coolant in the liquid aggregate state and thus a lower conversion of coolant into the vapor phase he follows.

With the comminution device designed according to the invention, in one embodiment particularly thermally sensitive materials, for example plastic plates, can be comminuted in one stage to a small grain size, for example <12 mm, without subsequent comminution, for example in cutting mills, being necessary. The comminution device according to the invention can ensure a high level of process reliability; moreover, the efficiency of the comminution device according to the invention can be improved compared to the conventional comminution device, which enables an increase in the material throughput with the same rotor drive power. The effective cooling of the material to be comminuted provided by the comminution device according to the invention can lead to a reduction in the wear of the comminution tools on the rotor or counter-knife(s) attached to the machine frame due to the reduced friction and thermal stress on the components. Another significant advantage of the crushing device according to the invention The comminution devices according to the prior art can consist in the omission of additional units for disposal of the used, heated cooling medium; moreover, the quantity of the cooling medium can be greatly reduced in the comminution device designed according to the invention.

The term “water-based liquid coolant” here means a coolant that essentially means water with a weight proportion of more than 80%, in particular more than 90%. In particular, the coolant can also consist entirely of water without any additives. However, it is also within the scope of the invention to use a water-based coolant with additives. For example, a soap additive can be added to the coolant in order to produce a washing process on the material at the same time as the cooling.

The statement "cooling capacity introduced into the comminution space" or "cooling capacity introduced into the material to be comminuted" can mean the cooling capacity provided by the coolant, which is absorbed by the material to be comminuted or the comminuted material, and thus leads to a reduction in the temperature of the material.

Further advantageous features and developments of the invention are specified in the following general description, the figures, the description of the figures and the dependent claims.

The cooling device or coolant device of the comminution device according to the invention can expediently have a coolant connection for connection to a coolant network such as a water supply network or a coolant reservoir include. If the pressure in the supply network is sufficient, the comminution device according to the invention can comprise a valve device for controlling the introduction, with which the introduction rate of the liquid, water-based coolant is controlled. In embodiments of the comminution device according to the invention, in which it comprises a coolant reservoir, a coolant pump can be included in order to set the specified introduction rate of the coolant, possibly in conjunction with a valve device, eg by determining the mass flow or volume flow of the coolant in the comminution process.

The statement "comminution space" can include an introduction space for receiving the material to be comminuted, including the construction space of the rotor. It can also be provided that this comminution space can be changed, for example, by a feed device such as a drivable slide of a feed device, in particular for moving material to be comminuted in the direction of the comminution rotor. It can also be provided according to the invention that the material to be comminuted can be introduced into the comminution chamber via a feed hopper, with a feed device also being able to be included in this embodiment.

It should be noted that the introduction of the liquid, water-based coolant into the comminution process can be carried out continuously or intermittently, with the statement "introduction rate of the coolant" or "quantity throughput of the comminution material" relating to a given period of time. This period of time can be, for example, in the range of seconds or also in the range of minutes.

To ensure that the shredded material does not exceed a specified moisture level or within a specified moisture degree range, it can be provided in the comminution device according to the invention that the control device is set up and configured to adapt the introduction rate of the coolant to the throughput of the material to be comminuted in the comminution process in such a way that more than 70% or more than 80%, in particular more than 90% of the coolant introduced changes from the liquid to the vapor phase when cooling the comminuted material or the comminuted material. Accordingly, the control device can be set up and configured to control the feeding rate in such a way that a predetermined degree of moisture content of the comminuted material is not exceeded or the degree of moisture content of the comminuted material is within a specified degree of moisture content range. This upper limit can correspond, for example, to a processing moisture content that specifies a maximum possible degree of moisture content in the comminuted material, for example a plastic granulate, at which the quality of the molded parts or semi-finished products formed therefrom is still assured. A usually permissible water content for processing plastics such as PE, PB, PA, PET can be around 0.02 to 0.1% by weight, which can be maintained for the comminuted material with the comminuting device according to the invention.

The comminution device according to the invention can expediently have at least one moisture sensor for detecting the degree of moisture in the comminuted material, in which case the control device can be designed to control a predetermined desired degree of moisture or a predetermined desired moisture range of the comminuted material with a manipulated variable that defines the introduction rate of the coolant or to regulate. Such a manipulated variable can include, for example, a control signal for a valve device and/or a coolant pump of the cooling device.

In order to prevent a specified temperature of the comminuted material from being exceeded when the comminution process is being carried out, it can expediently be provided that the comminution device according to the invention has at least one temperature sensor for detecting a temperature of the comminuted or partially comminuted material in the comminution chamber and/or for detecting a temperature of the comminuted material Goods outside the comminution chamber, wherein the control device is designed and set up to control or regulate the comminuted material to a predetermined target temperature or a predetermined target temperature range with a manipulated variable that defines the introduction rate of the coolant. This manipulated variable can be identical to the manipulated variable specified above for controlling the degree of moisture in the comminuted material. It is within the scope of the invention that the at least one temperature sensor for detecting the temperature of the comminuted material in the comminution chamber can be designed and arranged to detect the temperature of the comminuted material in the area of the comminution process, i.e. in an area of the comminution device in which the comminution process takes place, for example in the area of the rotor, under certain circumstances in the area of stationary to the machine frame arranged counter knives, since the comminution of the material to be comminuted takes place predominantly in these areas. For example, particularly in the case of such comminution devices in which a sieve device surrounds the comminution rotor on a partial circumference, at least one temperature sensor can be arranged and configured to record the temperature of the material to be comminuted that is still in the comminution process between the sieve and the rotor, i.e. within the comminution space . It is possible that at least one temperature sensor is arranged and designed to record the temperature of the comminuted material that has moved out of the effective range of the comminution rotor and thus out of the comminution chamber, for example after the comminution process was guided or fell down onto a conveyor belt arranged under the rotor.

Since the greatest waste heat from the process is generally generated in the area or at a short radial distance from the comminution tools of the rotor, it can expediently be provided that the comminution device according to the invention has at least one temperature sensor for detecting a temperature on the rotor, in particular a temperature in the area of one or more Includes comminution tools, wherein the control device is designed to regulate to a predetermined target temperature or a target temperature range of the rotor with a manipulated variable that defines the introduction rate of the coolant.

It can be provided that not only one of the above-mentioned input variables, but several, are included in the regulation by adjusting the introduction rate of the coolant into the comminution process or the comminution space, in particular the volume throughput of the comminuted material, the mass throughput of the comminuted material, a temperature of the comminuted material , a temperature of the material to be comminuted, a temperature at the rotor, a degree of moisture in the material to be comminuted and/or a degree of moisture in the material to be comminuted. In particular, it can be provided that the regulation includes at least the temperature and the degree of moisture of the comminuted material as control variables and is designed as a multivariable regulation, the respective setpoint value or setpoint range of the comminuted material being linked to a manipulated variable that determines the introduction rate of the coolant is regulated.

In order to provide a manipulated variable for the regulation, the cooling device of the comminution device according to the invention can comprise a connection device for connection to a coolant line network and/or for connection to a coolant reservoir as well as a coolant nozzle device comprising at least one coolant nozzle for introducing coolant into the comminution process or the comminution space, wherein the Control device for controlling the introduction rate of the coolant into the comminution chamber can be designed to control or set at least one flow valve of the coolant and/or at least one coolant pump. Depending on the embodiment, the manipulated variable can be a control signal for a coolant flow valve or a coolant pump, for example. In the control, for example, the manipulated variable can be designed to carry out a two-point control, i.e. in this case a flow valve or a valve device can be opened or closed or a coolant pump can be switched on or off. However, provision can also be made for the manipulated variable to be changed continuously, for example by providing corresponding control signals from the control device in order to continuously adjust the flow through the valve or the valve device or the pump capacity of the coolant pump. In the comminution device according to the invention, a flow rate sensor can expediently be provided for detecting the introduction rate of the coolant.

In order to convert the highest possible proportion of the coolant introduced into the comminution process or the comminution space into the gaseous phase, provision can be made for the coolant to be finely distributed in the comminution process or to introduce the crushing space, in particular in the form of a uniform nebulization, in order to bring about the lowest possible temperature of the crushed material and the lowest possible degree of moisture in the crushed material.

In order to provide a uniform introduction of the coolant, it can expediently be provided that the coolant nozzle device has a plurality of nozzles arranged at a distance from the longitudinal axis of the rotor on the machine frame of the comminution machine, it being possible for these nozzles to be arranged above the rotor in the installed position, so that the liquid coolant introduced is due to of its weight in the direction of the rotor or in a section in the area of the rotor, in which the respective comminution process essentially takes place. Provision can also be made for the coolant nozzle device to have a plurality of nozzles arranged at a distance from the longitudinal axis of the rotor on the circumference thereof for introducing the water-based coolant, it being possible for the nozzles to be aligned in the radial direction with respect to the rotor. In both variants, a nozzle device that discharges coolant continuously in the longitudinal direction of the rotor can also be used.

It can be provided that the coolant nozzle device is designed to apply the coolant to the rotor and/or to the material to be comminuted. For example, one or more nozzles can be directed towards the rotor and/or one or more nozzles can be directed towards the material to be comminuted in the area of the rotor. The statement "aligned" means an orientation for dispensing the liquid coolant in the direction of the rotor or the material to be comminuted or partially comminuted.

In order to increase the phase transformation of the coolant by providing a large surface area for the introduced coolant, it can expediently be provided that the coolant nozzle device is designed and set up to inject the aqueous coolant in the form of a water mist into the comminution process, in particular onto the rotor and/or the to introduce comminuted material in the area of the rotor, the water mist droplets having a diameter of <100 μm, in particular <50 μm. In particular, corresponding nozzles for introducing the liquid coolant can be designed to atomize the coolant so that the specified droplet size results.

In order to avoid exceeding a predetermined threshold value of the degree of humidity of the air in the region of the comminution device according to the invention during its operation, it can expediently be provided that the comminution device has a suction device which is designed for at least partially sucking off the coolant vapor developing during the cooling of the comminuted material , especially water vapor. Such a measure can be expedient in particular in a comminution device according to the invention, which generates increased process heat due to the material to be comminuted, which, as described in the device according to the invention, is essentially dissipated by the phase transition of the coolant.

In order to optimize the control behavior during operation of the comminution device according to the invention, it can have at least one moisture sensor for detecting the degree of moisture in the material to be comminuted, in particular outside the comminution space, and the control device can be designed depending on this as a further control variable to regulate the introduction rate for the coolant introduced into the comminution process.

In order to provide uniform cooling within the comminution process over the entire effective width (axial effective length) of the rotor, it can expediently be provided that the material to be comminuted is fed uniformly to the rotor, for example by means of a feed device acting over the effective width of the rotor, and the coolant device is designed via which Entire effective width of the rotor arranged material to be comminuted to provide an introduction of the coolant, in particular a uniform introduction over the effective width of the rotor.

The object specified above is also achieved by a method for cooling material to be comminuted and/or material that has been comminuted in a comminution device which is designed to carry out a comminution process in which comminution material located in a comminuting chamber of the comminution device is comminuted by means of comminution tools attached to the circumference of a comminution rotor is comminuted, wherein during the comminution process a water-based liquid coolant comprising at least 80% water is introduced into the comminution space or into the comminution process taking place in the comminution space. The method according to the invention is characterized in that an introduction rate of the coolant in the comminution process is adapted in such a way to an operating parameter of the device that is dependent on the throughput of the material to be comminuted, in particular a volume throughput of the material to be comminuted, a mass throughput of the material to be comminuted in the device, and/or a drive power of the rotor drive that more than 60% of the cooling capacity introduced into the shredded material provided by the latent heat of the water-based coolant.

As already explained above, the water-containing coolant can be introduced into the comminution process or the comminution space continuously or discontinuously. In both cases, according to the invention, this introduction rate is adapted to an operating parameter dependent on the throughput of the material to be comminuted, i.e. to the quantity of the material to be comminuted.

Depending on the embodiment, the rate at which the coolant is introduced can be adapted in such a way that more than 70%, in particular more than 75%, preferably more than 80% of the cooling capacity introduced into the material to be comminuted or into the comminution space is provided by the latent heat of the coolant introduced will.

In particular, in order to avoid a degree of moisture in the comminuted material that would aggravate the subsequent processing of the comminuted material, it can be expediently provided that the introduction rate of the coolant is adapted to the throughput of the comminuted material in the comminution process in such a way that more than 80%, in particular more than 90% of the coolant introduced changes from the liquid to the vapor phase when cooling the material to be comminuted or the comminuted material.

wobei dQ_Material/dt die in das zerkleinertem Gut eingebrachte Wärmeleistung, dm_Material/dt den Massendurchsatz des Zerkleinerungsgutes und Cp Material die spezifische Wärme des Zerkleinerungsgutes ist. In dem betrachteten Idealfall wird 100% der während des Zerkleinerungsprozesses in das Zerkleinerungsgut eingebrachte Wärmeleistung unter Nutzung der latenten Wärme des Kühlmittels beim Übergang in die dampfförmige Phase kompensiert. Für die folgende Betrachtung wird als Kühlmittel reines Wasser zugeführt mit einer Temperatur Ta, sodass sich eine spezifische Wärmemenge für dieses Kühlmittel ergibt zu: $${\mathrm{q}}_{\mathrm{Wasser}}=\left(\mathrm{4},\mathrm{18}\mathrm{kJ}/\left(\mathrm{kg}*\mathrm{K}\right)\right)*\left(\mathrm{100}-{\mathrm{T}}_{\mathrm{a}}\right)\mathrm{K}+\mathrm{2246}\mathrm{kJ}/\mathrm{kg}\mathrm{.}$$

To explain the adaptation of the introduction rate to the mass throughput of the material to be comminuted by the comminuting device according to the invention, it is assumed below that 100% of the coolant introduced changes from the liquid phase to the vapor phase when cooling the material to be comminuted or the comminuted material. Furthermore, it is assumed that the temperature of the material to be comminuted T _{input material} introduced into the comminution space should be identical to the temperature of the comminuted material, ie after the comminution process has been carried out under the effect of the described cooling. When carrying out the comminution of the material to be comminuted, the temperature of the comminuted material increases to T _{output material} due to the process heat without cooling . In this respect, the cooling capacity must be provided by the coolant: $${\dot{Q}}_{\mathit{material}}={\dot{m}}_{\mathit{material}}\ast c_{\mathit{material}}\ast \left(T_{\mathit{output}-\mathit{material}}-T_{\mathit{input}-\mathit{material}}\right)$$

where dQ _material /dt is the thermal output introduced into the comminuted material, dm _material /dt is the mass throughput of the material to be comminuted and Cp material is the specific heat of the material to be comminuted. In the ideal case under consideration, 100% of the thermal output introduced into the material to be comminuted during the comminution process is compensated by using the latent heat of the coolant during the transition to the vapor phase. For the following consideration, pure water is supplied as the coolant at a temperature Ta, resulting in a specific amount of heat for this coolant: $${\mathrm{q}}_{\mathrm{water}}=\left(\mathrm{4},\mathrm{18}\mathrm{kJ}/\left(\mathrm{kg}*\mathrm{K}\right)\right)*\left(\mathrm{100}-{\mathrm{T}}_{\mathrm{a}}\right)\mathrm{K}+\mathrm{2246}\mathrm{kJ}/\mathrm{kg}\mathrm{.}$$

With an exemplary introduction temperature Ta of 15° of the water, there is a specific amount of heat of $${\mathrm{q}}_{\mathrm{water}}=\mathrm{2602},\mathrm{15}\mathrm{kJ}/\mathrm{kg}\mathrm{.}$$

As such, when pure water is used as the coolant, the cooling by the occurrence of the latent heat accounts for more than 86% in the example described.

womit die Einbringrate für das Kühlmittel für den hier betrachteten Idealfall bestimmbar ist, bei welchem angenommen wird, dass das gesamte in den Zerkleinerungsprozess eingebrachte Kühlmittel in die dampfförmige Phase übergeht.The above considerations lead to the equation $${\mathrm{dm}}_{\mathrm{water}}/\mathrm{German}*{\mathrm{q}}_{\mathrm{water}}={\mathrm{dQ}}_{\mathrm{material}}/\mathrm{German},$$

whereby the introduction rate for the coolant can be determined for the ideal case considered here, in which it is assumed that all of the coolant introduced into the comminution process changes into the vapor phase.

The introduction rate of the coolant in the comminution process depends on the physical properties of the material to be comminuted, in particular the specific heat capacity, a transition temperature such as a melting temperature or a self-ignition temperature and must therefore be matched to the material in question.

In the method according to the invention, a temperature of the comminuted material can be measured and regulated to a predetermined target temperature or a target temperature range of the comminuted material with a manipulated variable that determines the rate of introduction of the coolant. Such a desired temperature can, for example, be below a melting temperature which, depending on the application, must be avoided during the comminution process in order not to make subsequent further processing more difficult, for example. For example, an actual temperature of the comminuted material can be measured and, if a specified temperature threshold is exceeded, the feed rate of the coolant can be increased, with preference being given to controlling to a specified target temperature with a manipulated variable that defines the feed rate of the coolant, for example a signal for operating a coolant pump and /or a coolant valve. Appropriately, at carrying out the method according to the invention, the introduction rate of the coolant is recorded, for example by measuring the mass or volume throughput of the coolant, from which the introduction rate can be determined, in particular calculated.

Provision can be made to measure a temperature on the rotor, in particular a temperature in the area of one or more comminution tools, and to regulate it to a predetermined target temperature or a target temperature range of the rotor with a manipulated variable that determines the rate of introduction of the coolant. Provision can also be made to use both a temperature of the rotor and a temperature of the comminuted material as a controlled variable with the feed rate as a manipulated variable. In order to avoid a degree of moisture that is not conducive to further processing of the comminuted material when carrying out the method according to the invention, it can be provided that a degree of moisture in the comminuted material is measured and adjusted to a specified target moisture level or a target moisture range of the comminuted material with a die Feed rate of the coolant defining manipulated variable is regulated. It can also be useful to measure the degree of moisture in the material to be comminuted, i.e. before the comminution process, with this measurement also being included in the regulation described.

In order to provide both a temperature control and a control of the degree of moisture of the comminuted material, it can be provided that in the method according to the invention both the temperature and the degree of moisture of the comminuted material are included as controlled variables and the control is thus designed as a multivariable control and the respective setpoint or setpoint range of the comminuted material with a manipulated variable that determines the rate of introduction of the coolant is regulated. In particular, it can be provided that the controlled system has a decoupling controller.

In order to provide the most homogeneous possible introduction of the cooling medium into the comminution chamber or the comminution process, which in the majority of designs takes place in the area of the comminution rotor, it can be provided that a plurality of locations spaced apart from the longitudinal axis of the rotor, at which nozzles or Nozzle devices can be arranged, the introduction of the coolant is carried out. Provision can also be made for the coolant to be introduced via nozzle devices which are attached or formed directly on the rotor. In this embodiment, the rotor can in this respect comprise at least one coolant supply line for guiding coolant to the nozzle devices.

For more precise control of the method according to the invention, it can be provided that a respective temperature of or in the comminuted material is detected by means of a plurality of spaced-apart temperature sensors and the control is carried out as a function of the plurality of temperatures detected by the temperature sensors. In the same way, a plurality of moisture sensors spaced apart from one another can detect a respective degree of moisture in the comminuted material and the control can be carried out as a function of the majority of moisture levels detected by the moisture sensors.

In order to provide as uniform as possible an introduction of the coolant into the comminution process, provision can be made for the coolant to be applied to the rotating rotor and/or to the material to be comminuted, in particular in the region of the rotor. Especially with those Crushing devices in which the comminution tools arranged on the rotor work together with associated counter-knives fixed in place on the machine frame can also be provided to introduce coolant in the area of the counter-knives or the counter-knife into the comminution space or the comminution process.

Depending on the arrangement of at least one nozzle of a nozzle device for introducing the coolant, in order to increase the surface area of the coolant and thus improve the cooling efficiency, it can be provided that the coolant is introduced in the form of a water mist for the comminution process, in which the water mist droplets have a diameter of <100 µm , in particular <50 microns.

In the method according to the invention, the introduction rate of the coolant can be adjusted as a manipulated variable of the regulation, in particular by means of control signals for a coolant valve device and/or by means of control signals for a coolant pump.

As explained at the outset, the method according to the invention and the device according to the invention also have the advantage over conventional devices that the heated coolant generally does not have to be removed from the comminuted material. In order to avoid an unacceptable level of humidity in the working environment of the comminution device, it can expediently be provided that the vaporous substance, in particular water vapor, developing during the cooling of the comminution process is at least partially sucked off. Such a vapor can, for example, be routed to the outside from the location of the comminution device and, in the case of pure steam, released in an environmentally friendly manner.

In one embodiment, the throughput or mass flow or the volume flow of the material to be comminuted can be measured directly and included in the regulation according to the invention. However, it is also possible to use the drive power of the motor driving the comminution rotor to infer the throughput or mass or volume flow of the material to be comminuted, so that the throughput of the material to be comminuted can be recorded indirectly by determining the drive power in order to adapt the feed rate of the coolant.

External influences on the comminution process, for example stored heat from machine components and/or the environment, which can also change during the operation of the device, can be compensated for with the explained regulations in the method according to the invention for cooling material to be comminuted and/or comminuted material. so that these disturbance variables mentioned by way of example as well as other disturbance variables that may occur and have an effect on the comminution process can be compensated for.

In principle, known controllers can be used for adapting the respective controller to the specific controlled system, for example PID or PI controllers. As shown, these controllers can be designed, for example, as single-point controllers, as multi-point controllers, in particular as two-point controllers, in order to map the respective time behavior of the controlled system.

Figur 1a

eine Ansicht auf eine erfindungsgemäß gestaltete Zerkleinerungsvorrichtung,

Figur 1b

in einer Funktionsprinzipskizze den Aufbau einer erfindungsgemäß gestalteten Zerkleinerungsvorrichtung,

Figur 2

ein Fließschema des Zerkleinerungsprozesses der Zerkleinerungsvorrichtung der Figur 1a, b,

Figur 3

zur Erläuterung des erfindungsgemäßen Verfahrens zum Kühlen von Zerkleinerungsgut ein Blockschaltbild eines Regelkreises für eine Einpunkt-Regelung bei der Durchführung des erfindungsgemäßen Verfahrens,

Figur 4

ein Blockschaltbild eines weiteren Regelkreises bei einer Zweipunkt-Regelung für die Durchführung des erfindungsgemäßen Verfahrens,

Figur 5

ein Blockschaltbild eines weiteren Regelkreises einer Zeitregelung für die Durchführung des erfindungsgemäßen Verfahrens und

Figur 6

ein Blockschaltbild einer Regelung zur Durchführung des erfindungsgemäßen Verfahrens, bei welcher neben der Führungs- und Regelgröße eine Mehrzahl von Betriebsparametern zur Festlegung der Regelung eingesetzt werden.

The invention is explained below by describing some embodiments of the comminution device according to the invention and the method according to the invention with reference to the accompanying figures, wherein

Figure 1a

a view of a crushing device designed according to the invention,

Figure 1b

in a functional principle sketch, the structure of a comminution device designed according to the invention,

figure 2

a flow chart of the crushing process of the crushing device of FIG Figure 1a , b ,

figure 3

to explain the method according to the invention for cooling material to be comminuted, a block diagram of a control loop for single-point control when carrying out the method according to the invention,

figure 4

a block diagram of a further control circuit in a two-point control for carrying out the method according to the invention,

figure 5

a block diagram of a further control circuit of a time control for carrying out the method according to the invention and

figure 6

a block diagram of a control system for carrying out the method according to the invention, in which, in addition to the command and control variable, a plurality of operating parameters are used to define the control system.

Figure 1a shows a crushing device 1 designed according to the invention in a perspective view. On a machine housing 10 is a crushing rotor 14 in Stored area of its two longitudinal ends, wherein in the embodiment described, the rotor 14 is moved by means of an electric drive motor 11.

In another embodiment, other drives, in particular hydraulic drives and/or drives comprising transmission devices, can also be used to move the comminution rotor 14 . The comminution rotor 14 has a plurality of comminution tools 15 on its circumference, which interact with a counter-knife device 16, which is arranged stationary relative to the machine housing 10 during the comminution operation, for comminuting the material to be comminuted. The shredded material is in the in Figure 1a The crushing device shown is introduced from above into the opening of a funnel 19 connected to the housing and then falls into the crushing space which is delimited at the bottom by the floor and the crushing rotor 14 . As understood by the present invention, the comminution rotor delimits this comminution space, but is part of it. In the illustrated embodiment, the comminution device can be arranged on a frame over a conveyor belt, so that the comminuted material falls onto the conveyor belt arranged below the comminution rotor, can be picked up by it and transported away.

To describe a design according to the invention in Figure 1a exemplified crushing device is on Figure 1b referenced, which shows functional areas of an inventively designed comminution device with reference to the invention. In the embodiment described, the material to be comminuted introduced into the comminution space is comminuted by the rotor 14 . The comminuted material or ground material then falls onto a below of the rotor 14 arranged conveyor belt 20, with which the material to be ground is transported, for example, in a memory. Sensors, in particular optical sensors, can be provided in the area directly below the rotor for detecting the condition of the ground material in order to record the actual value of the temperature and the degree of moisture content of the ground material. The temperature sensor 30 and the humidity level sensor 31 are provided for this purpose. Symbolic is in Figure 1b in addition, a mass sensor 32 is provided, which is designed to detect the mass flow of the material to be ground.

In order to cool the material to be comminuted or the material to be ground, the comminuting device 1 according to the invention has a coolant device which, depending on the embodiment, comprises several components for the configuration of the coolant device. In Figure 1b At the same time, two variants of a coolant device for designing the comminution device according to the invention are shown functionally, with the elements located in the rectangle marked with the reference number 46 being initially irrelevant for one embodiment. According to the invention, the cooling is carried out here with a water-based liquid coolant, the coolant having a water content of 100% in the described embodiments. In this respect, the cooling takes place through the use of pure water, so that the coolant device can be connected directly to a conventional water supply network by means of a conventional water connection 40 . In the embodiment described first, the inflow of the coolant can be adjusted via a two-way valve 42 and the volume flow of the coolant or of the water can be recorded via a volume flow measuring device 43 . The coolant is conducted via a line 41 to nozzles 48b of a nozzle device 48 arranged in the area of the rotor, via which the coolant, depending on the embodiment is introduced, for example, directly onto the rotor and/or into the crushing chamber. In order to ensure that the coolant is introduced as homogeneously and uniformly as possible, the coolant nozzle device 48 can comprise nozzles 48b spaced apart in the longitudinal direction of the rotor in order to introduce the coolant over the entire effective width of the rotor in accordance with its axial effective length. To improve the interaction of the coolant with the material in the crushing chamber, ie to optimize the material to be crushed and the partially or completely crushed material, it can be provided that specific nozzles, here water nozzles, are used that are designed to spray a fine water mist generate, wherein individual droplets have a diameter of <100 microns or even <50 microns, depending on the embodiment.

Particularly in those cases in which the water pressure of the water supply is not sufficient to apply the required pressure to the nozzle device with cooling water, provision can be made to integrate further components into the coolant device, which are shown in the dashed area 46 of Fig. 1b are specified. This relates to a water tank 44 connected to the water supply by means of the water connection 40 with fill level monitoring, to which a pump 45 is connected on the outlet side, which is also designed here to measure the volume flow delivered by the pump in the direction of the nozzles 48b.

In the embodiment described, the coolant device is controlled by means of a control device 55 which can be arranged in a switch cabinet 50 together with the control device 56 of the comminution rotor, ie the controller for controlling the rotor drive. The control devices 55, 56 can be coupled or combined in a central controller in order to couple the comminution process with the cooling process or to provide operating parameters of the comminution process, for example information about the drive power, which depends on the material flow of the material to be comminuted through the rotor , to be used for the control or regulation of the coolant device. In a similar way, cooling operating parameters can be forwarded from the controller of the coolant device to the controller of the rotor or the rotor drive in order to adapt the comminution to the operation of the coolant device.

In the Figure 1b The illustrated lines of the valve device 42, the volume flow measuring device 43, the water tank 44, the pump 45 and the sensors 30, 31, 32 to the controller 55 of the coolant device can, depending on the application, be used both for the transmission of control signals and data signals, possibly also bidirectionally, be trained.

figure 2 shows the representation of the Figure 1b with a higher degree of abstraction in the form of a flow chart, with relevant operating parameters or measured variables for the embodiment of the method according to the invention or the device according to the invention being specified. The material to be comminuted introduced into the comminuting space of the machine housing 10 has a moisture content FI. This is comminuted by means of the comminution rotor 14, with the drive motor 11 of the comminution rotor using an electrical drive power P. The material (ground material) comminuted by the rotor falls onto the conveyor belt 20, on which or in the area of which respective sensor devices are arranged for detecting the temperature TO of the comminuted material Guts (output material), the moisture level FO of the output material, the volume flow VO of the output material and/or the mass flow MO of the output material. The material to be ground which is transported away from the comminution device can be entered into a store 90, for example. The coolant is supplied with a volume flow VS, with the delivery of the coolant being controlled via a nozzle device 48 by means of the valve device 42 in this embodiment.

In the flow chart of figure 2 by definition, the process control is not specified. The described cooling of the material to be comminuted or partially comminuted material in the comminution chamber takes place to avoid elevated temperatures of the material to be comminuted. For this purpose, it can be provided that the device according to the invention is designed and set up to carry out a method in which the comminuted material, ie the material to be comminuted, the partially comminuted material and/or the comminuted material, is cooled by means of a water-based liquid coolant, with a Introducing rate, for example a volume flow or a mass flow of the coolant into the comminution process or the comminution space, is adapted to an operating parameter of the comminution device that is dependent on the throughput of the material to be comminuted, such as a volume throughput of the material to be comminuted, a mass throughput of the material to be comminuted and/or a drive power of the comminution rotor drive. According to the invention, this adaptation takes place in such a way that more than 60% of the cooling capacity introduced into the material to be comminuted is provided by the latent heat of the liquid coolant. Depending on the specific implementation of the method according to the invention, the percentage of the latent heat in the total cooling capacity can also be set to be larger, for example more than 70% or more than 80% of the cooling capacity.

If the heat output of the material dQ _MATERIAL /dt is completely converted into the cooling capacity of the coolant with complete transition of the coolant into the vapor phase, the above formula applies to the mass injection rate dm _WATER /dt = (dQ _MATERIAL /dt)*1/q _WATER or The volume injection rate VS= dV _WATER /dt = (dm _WATER /dt) * (1/ _QWATER ), where _{QWATER indicates} the density of the coolant, here water. According to the invention, depending on the design, the adjustment is made by controlling or regulating the feed rate VS of the coolant in the manner described, with the feed rate being reduced in accordance with the specified regulation if less than 60% of the cooling capacity introduced into the material to be comminuted is caused by the latent heat of the coolant provided. This exceeding of the threshold can be detected, for example, by the degree of moisture FO of the comminuted material indicating a correspondingly increased value, which means that the cooling capacity is provided to a lesser percentage by the latent heat of the coolant. Depending on the embodiment, provision can also be made, for example, to carry out a corresponding regulation or control in such a way that the adjustment of the introduction rate of the coolant to the throughput of the material to be comminuted in the comminution process is carried out in such a way that more than 70%, more than 80%, in particular more than 90% of the introduced coolant turns into the vapor phase during the cooling process. If this percentage is not reached, which can be detected, for example, by measuring an increased degree of moisture in the comminuted material, the introduction rate VS of the coolant can be reduced in this embodiment according to the invention.

It can be provided that in the method according to the invention or the comminution device according to the invention, the cooling of the material to be comminuted is regulated. For example, in one embodiment, a temperature of the comminuted material can be measured and regulated to a specified target temperature of the comminuted material with a manipulated variable that defines the introduction rate of the coolant; in this respect, the temperature of the comminuted material represents the controlled variable. figure 3 shows a corresponding control circuit 60 for carrying out an embodiment of the invention for such a control, wherein the reference variable w(t) is a predetermined temperature T _SOLL , which is generally dependent on the respective material to be comminuted. In the embodiment described, controller 61 is designed as a PI or PID controller. This outputs a control signal u(t) for controlling an actuator 62, which adjusts the manipulated variable volume flow VS of the coolant. In this respect, the actuator 62 corresponds to the valve device 42 of FIG figure 2 . The manipulated variable y(t) corresponds to this volume flow VS of the coolant. The controlled system 63 corresponds to the system part of the comminution device according to the invention between the location of the actuator 62 and the measuring element 64, ie in the embodiment according to FIG figure 2 the valve device 42 and the temperature sensor for detecting the temperature TO of the comminuted material. An expedient representation of the controlled variable also takes into account the effect of disturbance variables zi(t), for example the heat stored in the machine components and/or the ambient temperature as well as other external influences that affect the comminution process and/or the cooling process. The resulting temperature T0 of the comminuted material is recorded by the measuring element 64 and fed back for comparison with the reference variable w(t) (set temperature) and for determining the control deviation e(t), here ΔT=T _SET -TO.

In a further embodiment, with reference to the method according to figure 3 It can also be provided that a predetermined humidity level FO-Soll be specified as a reference variable for the control, with the control loop corresponding to the in figure 3 The control circuit shown can be constructed, i.e. the control circuit is implemented as a single-point control for controlling a specified degree of moisture content of the output material, with the introduction rate or the volume flow VS of the coolant acting as the manipulated variable and the degree of moisture content of the output material being the controlled variable .

figure 4 shows a further embodiment for the implementation of the method according to the invention, in which the control circuit 60b implements a two-point control, in which the valve device represents an actuator 63b, which is designed as a two/two-way valve. The actuator 63b adjusts the volume flow of the coolant in such a way that the temperature TO of the output material remains between an upper temperature limit T _{SOLL_} H and a lower temperature limit T _{SOLL_} L. While the controller 61a, b and the actuators 62a, b of the method according to the Figures 3 , 4 differ, the controlled system 63 is identical, provided that there are no other system-related changes.

figure 5 shows a further control circuit for implementing the method according to the invention, in which a predetermined time period t0 is given to the controller 61c as a further process variable, a maximum permitted temperature of the comminuted material T _{SOLL_} H is given as a reference variable and the actual temperature TO is again given via the measuring element 64 is detected. The control with the actual temperature TO of the comminuted material as a controlled variable is carried out here by appropriate design of the controller 61c such that the actuator 62c, in turn designed as a two/two-way valve, regulates the volume flow of the coolant is set in such a way that when the upper temperature limit T _{SOLL_} H is reached, coolant is supplied to the comminution process over a period of time t0, and heat output is thus withdrawn.

figure 6 shows a further control loop for implementing the method according to the invention, in which a maximum temperature of the comminuted material T _{SOLL_} H is used as the reference variable and the temperature TO of the comminuted material is used as the control variable. In contrast to the method according to the control loop figure 3 the control circuit has a controller 65, which can have both the control deviation ΔT and operating parameters or measured variables of the device as input variables, such as the drive power P, the mass flow MO or the volume flow VO of the comminuted material, the degree of moisture FI of the material to be comminuted good and/or the degree of moisture FO of the comminuted good. From this, controller 65 determines a control signal u(t) with which actuator 62, for example a valve device for adjusting a coolant flow, is controlled. In this way, for example, when the temperature of the ground material TO is regulated, the control device 65 can intervene if the degree of moisture FO of the ground material reaches impermissible values. For this purpose, the controller 65 can be set up to emit an output signal u(t), which serves as a control signal for the actuator in order to activate it to reduce the rate at which the coolant is introduced. A further input variable of the controller 65 can be, for example, a signal to indicate the direction of rotation of the comminution rotor. In this case, the regulator 65 can be set up to reduce the introduction rate of the cooling water or to set it to zero if this display signal indicates a reverse rotation of the comminution.

Reference List

1

crushing device

10

Machine housing, machine frame

11

drive motor

14

shredding rotor, rotor

15

shredding tools

16

counter knife

17

shredding room

17a

floor crushing room

18

feeding device

19

funnel

20

conveyor belt

30

temperature sensor

31

Humidity sensor, humidity sensor

32

mass sensor

40

water connection

41

water pipe

42

valve, valve device

43

Water volume flow measuring device

44

Water tank with level monitoring

45

water pump, coolant pump

48

nozzle device

48a

water nozzle, nozzle

50

switch cabinet

55

Control device of the cooling device

56

Control device of the shredding rotor

60

control loop

61

controller

62

actuator

63

controlled system

64

measuring element

80

Crushed material / grist

90

warehouse

TO

Temperature of shredded material (output)

vs

Injection rate, flow rate of the coolant

FI

Moisture level of the material to be shredded (input material)

P

Electrical drive power of the rotor drive

FO

Moisture level of the output material

VO

Volume flow of the output material

MON

Mass flow of the output material

w(t)

benchmark

TSOLL

target temperature

X(t)

controlled variable

u(t)

Actuation signal of the actuator

y(t)

manipulated variable

zI(t)

disturbance variable

e(t)

deviation

Claims (15)

Crushing device (1), which is designed to carry out a comminution process, having a comminution rotor (14) which is mounted on a machine frame (10) and has a plurality of comminution tools (15) on its circumference, the comminution rotor (14) being in one arranged in the comminuting space (17) receiving the material to be comminuted and designed to comminute the material located in the comminuting space, further comprising a coolant device designed to introduce a liquid coolant comprising at least 80% water into the comminuting space, and comprising a control device (55) for controlling the Coolant device for setting a feed rate of the coolant into the comminution space (17), characterized in that the control device (55) is set up and configured to adjust a feed rate (VS) of the liquid, water-based coolant in the comminution process to a volumetric throughput of the The operating parameters of the device (1) dependent on the material to be comminuted, in particular a volume throughput (VO), a mass throughput (MO) of the material to be comminuted, and/or a drive power (P) of the rotor drive (11a, 11b, 11c) in such a way that more than 60% of the cooling capacity introduced into the material to be comminuted is provided by the latent heat of the liquid, water-based coolant. Crushing device (1) according to claim 1,
characterized in that the control device (55) is set up and designed to adapt the introduction rate (VS) of the coolant to the throughput of the material to be comminuted in the comminution process in such a way that more than 80%, in particular more than 90%, of the coolant introduced during cooling of the shredded material changes from the liquid to the vapor phase. Crushing device (1) according to one of Claims 1 or 2, characterized in that
that the cooling device comprises a connection device (40) for connection to a coolant line network and/or for connection to a coolant reservoir (44) and a coolant nozzle device for introducing coolant into the comminution process or comminution space (17), the control device (55) for controlling the introduction rate of the coolant into the comminution space (17) controls at least one valve device (42) of the coolant and/or at least one coolant pump (45). Crushing device (1) according to any one of claims 1, 2 or 3, characterized by at least one temperature sensor (30) for detecting a Temperature (TO) of the comminuted material (80), the control device (55) being designed, to a predetermined desired temperature (T _SOLL ) or a predetermined desired temperature range of the comminuted material with a manipulated variable (y( t)) to regulate. Crushing device (1) according to one of Claims 1 to 4, characterized by at least one temperature sensor for detecting a temperature on the rotor (14), in particular a temperature in the region of one or more comminution tools (15), the control device (55) being embodied to regulate a predetermined target temperature (T _SOLL ) or a target temperature range of the rotor (14) with a manipulated variable (y(t)) that defines the introduction rate (VS) of the coolant. Shredding device (1) according to one of Claims 1 to 5, characterized by at least one moisture sensor (31) for detecting a degree of moisture (FO) of the comminuted material (80), the control device (55) being designed to set a predetermined desired degree of moisture or a to control the predetermined target moisture range of the comminuted material (80) with a manipulated variable (y(t)) that defines the introduction rate (VS) of the coolant. Crushing device (1) according to one of Claims 1 to 6, characterized by a suction device which is designed for at least partially sucking off the water vapor which develops during the cooling of the material to be comminuted. Process for cooling material to be comminuted in a Crushing device (1) designed to carry out a comminution process in which a comminution material located in a comminuting chamber (17) of the comminution device is comminuted by means of comminution tools (15) attached to the circumference of a comminution rotor (14), a liquid coolant being used during the comminution process at least 80% water is introduced into the comminution space (17), characterized in that s an introduction rate (VS) of the liquid, water-based coolant in the comminution process to an operating parameter of the device dependent on the throughput of the material to be comminuted, in particular a volume throughput (VO), a Mass throughput (MO) of the material to be comminuted, and/or a drive power (P) of the rotor drive (11a, 11b, 11c) is adjusted in such a way that more than 60% of the cooling capacity introduced into the material to be comminuted is generated by the latent heat of the liquid, water-based ated coolant is provided. Method according to Claim 8, characterized in that the adjustment of the introduction rate (VS) of the aqueous coolant to the throughput of the material to be comminuted in the comminution process is carried out in such a way that more than 80%, in particular more than 90% of the coolant introduced when cooling the material to be comminuted or The comminuted material changes from the liquid to the vapor phase. Method according to one of claims 8 or 9,
characterized in that a temperature (TO) of the comminuted material (80) is measured and a predetermined target temperature (T _SOLL ) or a target temperature range of the comminuted material is regulated with a manipulated variable (y(t)) that defines the introduction rate (VS) of the coolant. Method according to Claim 8, 9 or 10, characterized in that s a temperature on the rotor (14), in particular a temperature in the area of one or more comminution tools (15) is measured and adjusted to a predetermined target temperature or a target temperature range of the rotor with a feed rate the manipulated variable (y(t)) that defines the coolant. Method according to one of claims 8 to 11,
characterized in that a degree of moisture (FO) of the comminuted material is measured and regulated to a predetermined target degree of moisture or a target moisture range of the comminuted material with a manipulated variable that defines the introduction rate (VS) of the coolant. Method according to Claims 12, characterized in that the control comprises at least the temperature (TO) and the degree of moisture (FO) of the comminuted material as control variables and is designed as a multi-variable control, and the respective target value or target value range of the comminuted material with a feed rate of the coolant. Method according to one of claims 8 to 13,
characterized in that the introduction rate (VS) of the water-based coolant as a manipulated variable (y(t)) of the regulation by means of a coolant valve device (42) is set, with steam developing during the cooling of the material to be comminuted preferably being at least partially sucked off. Method according to one of claims 8 to 14,
characterized in that the degree of moisture (FO) of the material to be shredded is measured and, depending on this, the feeding rate (VS) is regulated as a further controlled variable.

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